1. Field of the Invention
The present invention relates to a method of controlling a condition in which a motor vehicle operates, e.g., the rate at which fuel is supplied to the engine on the motor vehicle, or the time at which the automatic transmission on the motor vehicle is actuated for a speed change, depending on parameters such as the opening of the throttle valve of the engine.
2. Prior Art
Modern motor vehicles incorporate automatic control systems which employ microcomputers or the like to control vehicle operating conditions depending on parameters such as the opening of the throttle valve of engines mounted on the motor vehicles. For example, one automatic motor vehicle control system controls the speed-changing operation of an automatic transmission according to a predetermined shift schedule map based on the vehicle speed and the throttle valve opening.
In the conventional automatic control system, the present value of the throttle valve opening and other present values are used as parameters for controlling the vehicle operating conditions. When the automatic transmission is controlled by the above automatic control system, therefore, the following problems arise upon a kickdown:
(1) After the throttle valve is opened, there is a certain time lag before a downshift is achieved.
(2) Since the transmission is shifted into a lower gear after the throttle valve has been opened and the rotational speed of the engine has increased, a large shock is produced by the gear shift.
(3) If the rotational speed of the engine were prevented from increasing until the downshift is finished in order to solve the problem (2) above, no large shock would be produced, but the time lag would be increased before the downshift is completed.
To solve the above problems at the same time, it would be desirable to predict how far the throttle valve will be opened when the throttle valve starts being opened and to control an automatic transmission depending on the predicted throttle valve opening. In this manner, a downshift would be completed quickly without a large shock being produced by such a downshift.
The rate at which fuel is supplied to an engine on a motor vehicle would also be controlled with a high response, using the above predicted control process.
However, since the throttle valve is opened in various different ways depending on the driver, road conditions, and other factors, it would be difficult to predict how far the throttle valve will be opened under every possible condition according to a fixed algorithm.